A262576 Concatenation of the numbers from 1 to n but omitting 6.

1, 12, 123, 1234, 12345, 123457, 1234578, 12345789, 1234578910, 123457891011, 12345789101112, 1234578910111213, 123457891011121314, 12345789101112131415, 1234578910111213141516, 123457891011121314151617, 12345789101112131415161718, 1234578910111213141516171819, 123457891011121314151617181920

Offset: 1

Author

N. J. A. Sloane, Sep 25 2015

Keywords

• nonn
• base

Comments

The only prime among the first 98 terms is a(6) = 123457. Does the sequence contain any other primes?

No additional primes through the first 2000 terms. - Harvey P. Dale, Sep 27 2018

Differs from A132943 at about the 28th terms.

No primes, other than a(6), through a(10000). - Robert Price, Nov 03 2018

Crossrefs

Cf. A132943.

Cf. A007908, A262299, A262571-A262582.

See A262300 for more about this problem.

Programs

Mathematica

Module[{nn=20,c},c=Drop[Range[nn],{6}];Table[FromDigits[Flatten[ IntegerDigits/@ Take[c,n]]],{n,nn-1}]] (* Harvey P. Dale, Sep 27 2018 *)